Question

I do the following code to check if an image exists:

 public bool DoesImageExist(string imageUrl)
{
    bool exists = false;
    try
    {
        HttpWebRequest request = (HttpWebRequest)System.Net.WebRequest.Create(imageUrl);
        request.Timeout = 5000;
        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            exists = (response.StatusCode == HttpStatusCode.OK);
        }
    }
    catch
    {
        exists = false;
    }

    return exists;
}

This works fine and returns a 404 for images that don’t exist, however since I switched on customErrors in the web.config, it started returning 200 status ok, because the image it requests returns a 404 and redirects to the error handler page which returns a 200 status ok. Is there a way around this to prevent the customErrors page from returning a 200 ok or working for images?

Answer 1

I found a quick way around this for anyone with the same problem by putting this code into my generic handler page (which I set in customErrors)

if (Request.Params.ToString().Contains("jpg") || Request.Params.ToString().Contains("png"))
        Response.StatusCode = 404;

This basically forces it to return a 404 for any jpeg/png images, however for all other errors it forces the generic page to be shown.